On Sunday, December 9, 2012 7:59:31 PM UTC-8, wrote:
For anyone who has slogged through the current thread on CD sound and won=
ders where the evidence really lies, here=92s a brief summary. There have b=
een numerous published DBTs of CD players and DACs, and the bottom line of =
the results agrees with the accepted theory of psychoacoustics experts: the=
re is no audible difference among conventionally designed products. The ver=
y rare differences that have been found can be explained by the unusual des=
igns in question.
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Published DBTs begin with the article cited in the other thread:
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Masters, Ian G. and Clark, D. L., "Do All CD Players Sound the Same?", St=
ereo Review, pp.50-57 (January 1986)
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If memory serves, they did find one CD player that was audibly distinguis=
hable from the others. I believe it was an early 14-bit model from Philips.
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Two later tests also appeared in SR:
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Pohlmann, Ken C., "6 Top CD Players: Can You Hear the Difference?", Stere=
o Review, pp.76-84 (December 1988)
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Pohlmann, Ken C., "The New CD Players, Can You Hear the Difference?", Ste=
reo Review, pp.60-67 (October 1990)
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Both tests found no differences among players.
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The Sensible Sound did a two-part report on another test:
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CD Player Comparison, The Sensible Sound, # 75, Jun/Jul 1999.=20
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CD Player Comparison, The Sensible Sound, # 74, Apr/May 1999.
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My understanding is that they did not identify the actual players being t=
ested, except for the cheapest one, which was a sub-$100 carousel model. Ag=
ain, no differences were found.
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A group in Spain has posted results of numerous tests it has done. A full=
list of tests is here, unfortunately in Spanish:
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http://www.matrixhifi.com/marco.htm
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(click on Pruebas Ciegas to see the list)
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Most of their tests found no audible differences. (See, for example, thei=
r comparison of a Benchmark DAC to a Pioneer DVD player.) Devices that did =
sound different:
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1) a non-oversampling DAC
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2) a device with a tubed output stage
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3) a portable Sony Discman, connected via its headphone output
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Two further points:
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1) No quantity of DBTs can prove a negative. But believers in CD/DAC soun=
d can cite no comparable empirical evidence whatsoever for their position.
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2) Psychoacoustics researchers have reached the same conclusion via other=
means. Here=92s a standard textbook in the field:
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Moore, BCJ. An Introduction to the Psychology of Hearing, Fourth Edition.=
San Diego: Academic Press, 1997.
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And here=92s what Dr. Moore had to say about the issue:
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=93CD and DAT players generally have a specification which is far better =
than that of other components in a hi-fi system, especially cassette decks =
and loudspeakers. Essentially, the output signal which they provide is indi=
stinguishable from that which would be obtained from the master tape produc=
ed by the recording studio (studio recordings are now usually digital recor=
dings). Thus, provided a CD or DAT player is working according to specifica=
tion, it will produce no noticeable degradation in sound quality. It follow=
s from this that most CD players and DAT players sound the same.=94
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That is all.
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bob
The SR reviews are suspect due to SR's editorial policy which was=20
that everything printed in SR must serve the advertisers/potential
advertisers. That meant no critical evaluations of anything. Ever=20
wonder why SR never published a negative review from Julian
Hirsch? Because it was SR policy to not publish negative reviews.
That didn't mean that Julian never came across a piece of equipment
that didn't meet its public specs. It simply meant that SR didn't run
the review, that's all. You see, it was their editorial policy to cater
to the industry, not the consumer. It is because of this policy that
the late J. Gordon Holt founded Stereophile. His stint at High-Fidelity=20
Magazine (and I believe that he also worked at SR for a time too)
convinced him that these magazines weren't serving the interest=20
of the consumer. That's also why that no one should be surprised
that SR's tests on the audibility of components, including CD players,
show no differences in audible performance. It's also where the joke
"quote" from Julian Hirsch goes like this: "of all the amplifiers that I
have ever tested, this was one of them" That "quote" applies to=20
tuners, CD decks, preamps, receivers, you name it. And no, Julian=20
never really said that, but if you read the sum-total of his work,=20
including going back to "Hirsch-Houck" labs before Julian went off
on his own, you will see that he never had an opinion. He just=20
measured the equipment against its published specs, and if it met
them, it was good for go. If not, that fact was never mentioned (as
far as I know and I subscribed to SR for decades!) and the reviews
were not published. The fact that to SR, everything sounded the same
was sacrosanct. I don't wonder that all of those "DBTs" showed no=20
difference in CD players.
I won't comment on the Sensible Sound tests because I've only seen
a couple of issues of that magazine and don't know what their=20
editorial policy was.=20
As for the early Philips (Magnavox) players sounding "different" in=20
one of those tests, I agree. It did sound different from the early
Japanese players. It was listenable, the early Sonys, Kyoceras,=20
and Technics players were not and that's MY opinion. =20